Basic Surgery (100q).1

2.

Which of the following statement(s) is/are true concerning the cell function of phagocytosis?

Phagocytosis is a mechanistically distinct process of endocytosis performed by special cells to take up larger particles such as bacteria or erythrocytes
Lymphocytes are the primary blood cell involved with this process
The process involves a coating of the cytoplasmic surface known as clathrin
Phagocytosis is performed only by white blood cells and tissue macrophages

Correct Answer

A. Phagocytosis is a mechanistically distinct process of endocytosis performed by special cells to take up larger particles such as bacteria or erythrocytes

Explanation

Phagocytosis is a specialized form of endocytosis by which large particles are internalized by specialized cells primarily macrophages and neutrophils. To be phagocytosed, particles must bind to the surface of the phagocytic cell, usually as the result of specific antibody coating the particle. The phagocytic cell then extends pseudopods which engulf the particle. This event is followed by membrane fusion and a pinching off. As opposed to endocytosis, this process does not involve the membrane protein, clathrin, but rather actin. A physiologically relevant site of phagocytosis is the thyroid gland, where thyroid follicular cells phagocytose and digest thyroglobulin from the lumen of the thyroid follicle, thereby releasing the thyroid hormones, thyroxine triiodothyronine.

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3.

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

Age over 70 years.
Chronic malnutrition.
Controlled diabetes mellitus.
Long-term steroid use.
Infection at a remote body site.

Correct Answer

A. Controlled diabetes mellitus.

Explanation

Controlled diabetes mellitus has been shown repeatedly not to be associated with increased likelihood of incisional infection provided one avoids operations on body parts that may be ischemic or neuropathic. Uncontrolled diabetes mellitus, such as ketoacidosis, is associated with a dramatic increase in surgical infection. The other parameters noted—age over 70, chronic malnutrition, regular steroid use, and an infection at a remote body site—are well-recognized adverse predictive factors and are identified in tables within the chapter.

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4.

Advantages of epidural analgesia include:

Earlier mobilization after surgery.
Earlier return of bowel function.
Shorter hospitalizations.
Decreased stress response to surgery.
All of the above

Correct Answer

A. All of the above

Explanation

Epidural analgesia include excellent pain relief, decreased sedation with more rapid recovery to presurgical levels of consciousness, earlier mobilization after surgery with increased ability to co-operate with respiratory therapy and physical therapy. Following vascular surgery epidural analgesia may also improve graft flow through mild sympathetic blockade. Earlier return of bowel function, decreased stress response, shorter hospitalizations, and decreased morbidity have all been associated with epidural analgesia.

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1

5.

Which of the following factors have been demonstrated to promote wound healing in normal individuals?

Vitamin A supplementation
Vitamin C supplementation
Vitamin E application to the wound
Zinc supplementation
None of the above

Correct Answer

A. None of the above

Explanation

Several important systemic factors or conditions influence wound healing. Interestingly, there are no known systemic conditions that lead to enhanced or more rapid wound healing. Overall nutrition as well as adequate vitamins play an important role in wound healing. Vitamin A is involved in the stimulation of fibroplasia, collagen cross-linking, and epithelialization. Although there is no conclusive evidence in humans, vitamin A may be useful clinically for steroid-dependent patients who have problematic wounds or who are undergoing extensive surgical procedures. Vitamin C is a necessary cofactor in hydroxylization of lysine and proline in collagen synthesis and cross-linkage. The utility of vitamin C supplementation in patients who otherwise take in a normal diet has not been established. Vitamin E is applied to wounds and incisions empirically by many patients. The evidence to support this practice is entirely anecdotal. In fact, large doses of vitamin E have been found to inhibit wound healing. Zinc and copper are also important cofactors for many enzyme systems that are important to wound healing. Deficiency states are seen with parenteral nutrition but are rare and readily recognized and treated with supplements. Overall, vitamin and mineral deficiency states are extremely rare in the absence of parenteral nutrition or other extreme dietary restrictions. There is no evidence to support the concept that supranormal provision of these factors enhance wound healing in normal patients.

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1

6.

The characteristic changes that follow a major operation or moderate to severe injury do not include the following:

Hypermetabolism.
Fever
Tachypnea
Hyperphagia
Negative nitrogen balance.

Correct Answer

A. Hyperphagia

Explanation

The characteristic metabolic response to injury includes hypermetabolism, fever, accelerated gluconeogenesis, and increased proteolysis (creating a negative nitrogen balance). Food intake is generally impossible because of abdominal injury or ileus. With time, food intake increases, but the patient generally experiences anorexia, not hyperphagia.

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7.

In patients receiving massive blood transfusion for acute blood loss, which of the following is/are correct?

Packed red blood cells and crystalloid solution should be infused to restore oxygen-carrying capacity and intravascular volume.
Two units of FFP should be given with every 5 units of packed red blood cells in most cases
A “six pack” of platelets should be administered with every 10 units of packed red blood cells in most cases.
One to two ampules of sodium bicarbonate should be administered with every 5 units of packed red blood cells to avoid acidosis.
One ampule of calcium chloride should be administered with every 5 units of packed red blood cells to avoid hypocalcemia.

Correct Answer

A. Packed red blood cells and crystalloid solution should be infused to restore oxygen-carrying capacity and intravascular volume.

Explanation

Patients who are suffering from acute blood loss require crystalloid resuscitation as the initial maneuver to restore intravascular volume and re-establish vital signs. If 2 to 3 liters of crystalloid solution is inadequate to restore intravascular volume status, packed red blood cells should be infused as soon as possible. There is no role for “prophylactic infusion” of FFP, platelets, bicarbonate, or calcium to patients receiving massive blood transfusion. If specific indications exist patients should receive these supplemental components. In particular, patients who have abnormal coagulation tests and have ongoing bleeding should receive FFP. Patients who have depressed platelet counts along with clinical evidence of oozing (microvascular bleeding) benefit from platelet infusion. Sodium bicarbonate is not necessary, since most patients who receive blood transfusion ultimately develop alkalosis from the citrate contained in stored red blood cells. The use of calcium chloride is usually unnecessary unless the patient has depressed liver function, ongoing prolonged shock associated with hypothermia, or, rarely, when the infusion of blood proceeds at a rate exceeding 1 to 2 units every 5 minutes.

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8.

In “catabolic” surgical patients, which of the following changes in body composition do not occur?

Lean body mass increases.
Total body water increases.
Adipose tissue decreases.
Body weight decreases.

Correct Answer

A. Lean body mass increases.

Explanation

Lean body mass represents the body compartment that contains protein. Because critical illness stimulates proteolysis and increased excretion of body nitrogen, this compartment is consistently reduced, not increased. The change in body composition is associated with a loss of body weight, an increase in total body water, and a decrease in body fat.

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9.

Which of the following statement(s) is/are true concerning pulmonary edema?

Pulmonary edema effectively narrows bronchi and increases pulmonary vascular resistance
Ventilation and perfusion are decreased equally
Positive pressure ventilation improves gas exchange by decreasing lung edema
The condition is frequently caused by decreased plasma protein levels

Correct Answer

A. Pulmonary edema effectively narrows bronchi and increases pulmonary vascular resistance

Explanation

The causes of pulmonary edema are: 1) increased hydrostatic pressure; 2) increased capillary permeability and 3) decreased plasma oncotic pressure. The latter, however, is rarely a problem unless the concentration of plasma protein is very low. When fluid begins to collect in the lung interstitium, it migrates to the loose areolar portion of the lung microanatomy that surround the small bronchioles and pulmonary arteries. The edema in these areas has the effect of narrowing bronchi and increasing resistance in the pulmonary vasculature. This will decrease both ventilation and perfusion in the edematous area, but ventilation is often affected more than blood flow, resulting in a decreased / ratio, with all of its attendant effects on gas exchange. Ventilator treatment of pulmonary edema which increases airway pressure tends to hold the alveoli open, spreading out the space available for water accumulation and overcomes the effect of small bronchial occlusion. Positive pressure ventilation does not, therefore, affect the amount of edema in the lung, only its manifestations.

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10.

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

Age over 70 years.
Chronic malnutrition.
Controlled diabetes mellitus.
Long-term steroid use.
Infection at a remote body site.

Correct Answer

A. Controlled diabetes mellitus.

Explanation

Controlled diabetes mellitus has been shown repeatedly not to be associated with increased likelihood of incisional infection provided one avoids operations on body parts that may be ischemic or neuropathic. Uncontrolled diabetes mellitus, such as ketoacidosis, is associated with a dramatic increase in surgical infection. The other parameters noted—age over 70, chronic malnutrition, regular steroid use, and an infection at a remote body site—are well-recognized adverse predictive factors and are identified in tables within the chapter.

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11.

Which of the following statement(s) is/are true concerning the compensatory mechanisms and treatment of metabolic acidosis?

Maximal renal compensation for metabolic acidosis occurs before full respiratory compensation can occur
All patients with lactic acidosis should receive prompt treatment with bicarbonate
Potassium replacement is essential even in the face of normal or high serum potassium when treating diabetic ketoacidosis
Sodium bicarbonate administration should begin simultaneous with volume resuscitation in patients with hypoxia secondary to shock

Correct Answer

A. Potassium replacement is essential even in the face of normal or high serum potassium when treating diabetic ketoacidosis

Explanation

The kidney is extremely sensitive to changes in serum bicarbonate concentration and responds by increasing net acid excretion primarily by increasing ammonia excretion. Maximal renal compensation requires 2 to 4 days. Delay in achieving maximal renal response to an increased acid load causes blood pH to decline, which stimulates hyperventilation. Although effective in promptly raising blood pH, ventilatory compensation is only partial, and full respiration compensation requires 12 to 24 hours. The major principal of treatment for mild to moderate acute metabolic acidosis is correction of the underlying cause. In surgical and trauma patients, metabolic acidosis is often the result of hypoxia secondary to inadequate tissue perfusion and subsequent lactic acidosis. Volume and/or blood resuscitation alone may be enough to correct the acidosis. Attempts to correct acidosis with exogenous bicarbonate before correction of inadequate tissue perfusion are usually unsuccessful. The use of bicarbonate for the treatment of lactic acidosis is controversial at best. In several studies the use of bicarbonate in patients with lactic acidosis does not improve clinical parameters or outcome. The correction of both acidosis and hypoglycemia of diabetic ketoacidosis is best achieved by the administration of insulin. Volume resuscitation is also required. Potassium replacement is essential, even in the face of normal or high serum potassium, and as hypokalemia develops as acidosis in hyperglycemia are corrected

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12.

Which of the following statement(s) is/are correct concerning the body fluid compartments?

Both the extracellular and intracellular components of total body water can be directly measured
The intravascular space accounts for the majority of extracellular fluid
All water in the interstitial space is freely exchangeable
Transcellular fluid, separated from other compartments by both endothelial and epithelial barriers, constitute about 4% of total body water

Correct Answer

A. Transcellular fluid, separated from other compartments by both endothelial and epithelial barriers, constitute about 4% of total body water

Explanation

Total body water (TBW) is distributed within the intracellular and extracellular compartments. Intracellular fluid cannot be measured directly but is calculated as the difference between TBW and the measured extracellular water. Extracellular fluid can be measured directly. The extracellular fluid compartment can be further simplified into the intravascular and interstitial spaces. Intravascular space, which accounts for 20% of the extracellular fluid, contains the plasma volume which is approximately 8% of TBW or 5% of body weight. The interstitial space extends from the blood vessels to the cells themselves and includes the complex ground substance making up the acellular matrix of tissue. Although the water within the space is thought to be freely exchangeable, this water exists in two phases. The free phase contains water that is generally freely exchangeable and in a constant state of flux. The bound or gel phase is composed of water that is closely associated with glycosaminoglycans, mucopolysaccharides, and other matrix components. This water is much less freely exchangeable. An additional extracellular fluid compartment, the transcellular compartment, consists of water that is poorly exchangeable under normal circumstances. This fluid is separated from other compartments by both endothelial and epithelial barriers and includes cerebrospinal fluid, synovial fluid, water within cartilage and bone, fluids of the eye, and the lubricating fluids of the serous membranes. Together, these fluids constitute about 4% of TBW.

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13.

Intensive insulin therapy:

Prevents the aggressive development of atherosclerosis in diabetic patients
Is not associated with unawareness of hypoglycemia.
Improves peripheral neuropathy
Improves established retinopathy and nephropathy
Is indicated in all patients with non–insulin-dependent diabetes mellitus (NIDDM).

Correct Answer

A. Improves peripheral neuropathy

Explanation

Intensive insulin therapy is indicated in patients with IDDM who can actively participate in their own management and the attainment of the goals set for their blood glucose and glycosylated hemoglobin (HgA1 c) levels. Because the main complication of intensive therapy is iatrogenic hypoglycemia, this mode of treatment is not indicated for patients with NIDDM, who often have coexisting medical conditions such as coronary artery disease and who tolerate hypoglycemia poorly. There is little or no evidence that macrovascular disease is affected by intensive insulin therapy, and the added weight gain and hyperinsulinemia associated with the therapy may worsen atherosclerosis. Unawareness of hypoglycemia is directly related to a recent hypoglycemia episode, so patients treated intensively are often unaware of the problem. Intensive therapy does not improve established retinopathy or nephropathy but slows or prevents progression of these complications; however, better glucose control may improve peripheral neuropathy.

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14.

Which of the following statement(s) is/are true concerning the treatment of pulmonary interstitial edema?

Diuresis and blood transfusion is a valuable step
Salt-poor albumin leaks through the capillaries and worsens the condition
Mannitol is contraindicated as a diuretic in this clinical situation
Isoproterenol is a poor choice as an ionotropic agent

Correct Answer

A. Diuresis and blood transfusion is a valuable step

Explanation

Treatment of pulmonary edema has two important goals, the first is to improve oxygenation if it is impaired, and the second is to minimize fibrosis and bacterial infection, which often accompany pulmonary edema caused by capillary injury. The treatment of interstitial edema is to maintain the hydrostatic pressure as low as compatible with adequate cardiac output and to raise the oncotic pressure selectively in the vascular space. These measures, combined with fluid restriction and diuresis, will decrease the amount of pulmonary edema. Since it is desirable to maintain filling pressures of the left ventricle as low as possible while maintaining a good cardiac output, inotropic drugs to improve left ventricular contractility are helpful. Isoproterenol or dopamine should be used, with serial cardiac output and filling pressure measurements. The first step in decreasing pulmonary edema is to decrease the pulmonary capillary hydrostatic pressure as low as is compatible with an adequate cardiac output. This is done by diuresis and fluid restriction. As the patient falls behind in blood volume, signs of hypovolemia may appear. Blood volume is then replenished with a fluid that stays in the vascular space. Packed red cells are ideal for this application. When the hematocrit is normal, concentrated salt-poor albumin should be used. This hyperoncotic fluid replenishes the blood volume by attracting interstitial fluid from throughout the body into the vascular space and supplements diuresis. This technique is useful even in the septic patient who may have increased capillary permeability and may loose albumin from the vascular space at a rapid rate. Even if albumin “leaks out”, the short term effects of expanding blood volume and decrease in edema will appear.

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15.

Shock can best be defined as:

Hypotension
Hypoperfusion of tissues.
Hypoxemia
All of the above.

Correct Answer

A. Hypoperfusion of tissues.

Explanation

Shock, no matter what the cause, is a syndrome associated with tissue hypoperfusion. Tissue hypoperfusion leads to tissue hypoxia, which may or may not be due to hypoxemia. Hypotension is a late sign of shock and, therefore, is not a good clinical indicator of the presence of tissue hypoperfusion.

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2

16.

A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance of these differences is/are true?

The cell membrane is able to maintain a 10,000 fold gradient between the extracellular concentration of ionized calcium and the intracellular concentration
The key to these differences is the fact that the plasma membrane is normally impermeable to sodium, potassium and calcium
The selectivity of biologic membranes is highly consistent and seldom changes
The selectivity of cell membranes relates only to ions and not organic compounds

Correct Answer

A. The cell membrane is able to maintain a 10,000 fold gradient between the extracellular concentration of ionized calcium and the intracellular concentration

Explanation

The survival of the cell requires that cytosolic composition be maintained within narrow limits, despite the constant influx of nutrients and the simultaneous outflow of waste. A familiar example of the distribution of ions across the cell membrane is that of sodium and potassium. Cells are typically rich in potassium and contain very little sodium. Despite the fact that they are constantly bathed by fluid that is precisely the opposite composition. Even more impressive is the distribution of ionized calcium. The extracellular concentration of this ion is typically of the order of 10–3M, whereas that of cytosol is typically 10–7M, a 10,000-fold gradient. Such nonequilibrium ion distributions are even more remarkable in light of the fact that the plasma membrane is, to varying degrees, leaky to ions such as sodium, potassium and calcium. The plasma membrane is leaky to a variety of substances, but it exhibits an astonishing ability to discriminate or select one substance over another. This selectivity relates to not only ions but also for organic compounds such as glucose. Finally, the selectivity of biologic membranes can be altered drastically as a result of regulatory or signaling processes that occur within the cell.

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17.

Glucose overload results in increased CO 2 production. Which of the following statements are true?

In patients with respiratory insufficiency, administration of glucose as a principal calorie source is contraindicated
In patients with pulmonary infection and sepsis, calorie support should consist of 95% fat and 5% glucose.
In Askanazi's study, increased CO 2 production and difficulty in weaning was associated only with pronounced overfeeding.
CO 2 production should be measured in most patients who are supported by respirators in intensive care units and are receiving nutritional support

Correct Answer

A. In Askanazi's study, increased CO 2 production and difficulty in weaning was associated only with pronounced overfeeding.

Explanation

Few papers have excited as much interest as that by Askanazi, Kinney, and co-workers, which demonstrated that glucose calories given to patients with severe respiratory impairment may result in difficulty in weaning from a respirator. Subsequent research has suggested, however, that this occurs only with severe overfeeding, when the respiratory quotient is greater than 1 and calories are excessive. If one examines the conditions under which Askanazi's patients were studied, these were a group of septic, depleted patients who were taken from almost no nutritional support to a caloric supply of 2.25 times their caloric requirement, most of the calories consisting of glucose. Suffice it to say that, in patients with impaired respiratory function, one should measure VCO2 and, when VCO2 is significantly elevated and appears to interfere with weaning, decrease the amount of glucose calories and increase the amount of fat. If one measures or estimates calorie requirements and does not overfeed, lipid can be utilized for 25% of the caloric requirement and glucose for the remainder, without much fear of excessive CO 2 production.

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18.

All of the following are true about neurogenic shock except:

There is a decrease in systemic vascular resistance and an increase in venous capacitance.
Tachycardia or bradycardia may be observed, along with hypotension.
The use of an alpha agonist such as phenylephrine is the mainstay of treatment
Severe head injury, spinal cord injury, and high spinal anesthesia may all cause neurogenic shock.

Correct Answer

A. The use of an alpha agonist such as phenylephrine is the mainstay of treatment

Explanation

Neurogenic shock occurs when severe head injury, spinal cord injury, or pharmacologic sympathetic blockade leads to sympathetic denervation and loss of vasomotor tone. Both arteriolar and venous vessels dilate, causing reduced systemic vascular resistance and a great increase in venous capacitance. The patient's extremities appear warm and dry, in contrast to those of a patient in cardiogenic or hypovolemic shock. Tachycardia is frequently observed, though the classic description of neurogenic shock includes bradycardia and hypotension. Volume administration to fill the expanded intravascular compartment is the mainstay of treatment. The use of alpha-adrenergic agonist is infrequently necessary to treat neurogenic shock.

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19.

Narcotics are commonly used in the administration of general anesthesia. Which of the following statement(s) is/are true concerning this class of agents.

Narcotics have both profound analgesic and amnestic properties
Narcotics can cause hypotension by direct myocardial depressive effects
Naloxone should be used routinely for the reversal of narcotic analgesia
Acutely injured hypovolemic patients are at significant risk for decreased blood pressure with the use of narcotic analgesics
Propofol is a new intravenous short-acting narcotic used frequently in the outpatient setting

Correct Answer

A. Acutely injured hypovolemic patients are at significant risk for decreased blood pressure with the use of narcotic analgesics

Explanation

Narcotics and synthetic analogues belong in the class of drugs called opioids. Narcotics produce profound analgesia and respiratory depression. They have no amnesic properties, no myocardial depressive effects, and no muscle relaxant properties. Narcotics may produce significant hemodynamic effects indirectly through the release of histamine and/or blunting of the patient’s sympathetic vascular tone due to analgesic properties. Acutely injured patients may be hypovolemic and in pain, with high sympathetic tone and peripheral resistance. Therefore, such patients can experience a dramatic drop in systemic blood pressure with minimal doses of opioids. All opioids can be reversed with naloxone. Naloxone reversal, however, can be dangerous because the agent acutely reverses not only the analgesic effects of the opioid but also analgesics effects of native opioids. Naloxone treatment has been associated with acute pulmonary edema and myocardial ischemia and should not be used electively to reverse the effects of narcotic. Propofol is a lipid-soluble substitute isopropyl phenol non-narcotic agent that produces rapid induction of anesthesia followed by awakening in four to eight minutes.

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2

20.

Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true?

Careful monitoring of prothrombin time and aPTT time are necessary to avoid bleeding complications
A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding
Recent (less than 10 days) major surgery is a contraindication to systemic but not regional fibrinolytic therapy
A patient with a cerebrovascular event occurring less than two months ago can be treated with fibrinolytic therapy if head CT scan is normal

Correct Answer

A. A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding

Explanation

Fibrinolytic therapy induces a hemostatic defect through a combination of factors. Hypofibrinogenemia and fibrin degradation products inhibit fibrin polymerization and, in combination with a decrease in the clotting factors V and VIII, prolong the ability of blood to clot. However, coagulation tests in general do not correlate well with bleeding complications. A level of fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding. Absolute contraindications to thrombolytic therapy include active internal bleeding, recent (less than 2 months) cerebral vascular accident, and documented left heart thrombosis. Recent (less than 10 days) major surgery, obstetric delivery, organ biopsy, or major trauma is considered a major relative contraindication to either regional or systemic thrombolytic therapy.

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21.

Which of the following statements about the presence of gallstones in diabetes patients is/are correct?

Gallstones occur with the same frequency in diabetes patients as in the healthy population.
The presence of gallstones, regardless of the presence of symptoms, is an indication for cholecystectomy in a diabetes patient.
Diabetes patients with gallstones and chronic biliary pain should be managed nonoperatively with chemical dissolution and/or lithotripsy because of severe complicating medical conditions and a high operative risk.
The presence of diabetes and gallstones places the patient at high risk for pancreatic cancer.
Diabetes patients with symptomatic gallstones should have prompt elective cholecystectomy, to avoid the complications of acute cholecystitis and gallbladder necrosis.

Correct Answer

A. Diabetes patients with symptomatic gallstones should have prompt elective cholecystectomy, to avoid the complications of acute cholecystitis and gallbladder necrosis.

Explanation

Gallstones have been found to be very prevalent in patients with type II (non–insulin-dependent) diabetes mellitus, perhaps related to the dyslipoproteinemia in such patients. Although the complications of acute cholecystitis (infection, sepsis, gangrene of the gallbladder) are more common in diabetics, a decision-analysis study has shown that prophylactic cholecystectomy cannot be justified since the risk of morbidity and/or mortality from the cholecystectomy procedure is as great as that of complications or death from acute cholecystitis. Patients who become symptomatic should be promptly prepared and should undergo elective cholecystectomy, because an emergency operation in these patients with comorbid conditions, especially coronary artery disease, has substantial added mortality associated with it. There is no causal relationship between diabetes and pancreatic cancer.

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22.

Which of the following statement(s) is/are correct concerning the cardiovascular response to shock?

Changes in cardiac contractile function shift the Frank Starling curve up and down
Venoconstriction from skeletal muscle is a significant contributor to the restoration of blood volume with shock
Arterial vasoconstriction affects all vascular beds equally
The total circulating blood volume is equally split between the arterial and venous system

Correct Answer

A. Changes in cardiac contractile function shift the Frank Starling curve up and down

Explanation

Central in the general cardiovascular response to shock is the action of the heart itself. The principle determinants of cardiac function in the normal heart are the volume of blood available for the heart to pump (preload), the systolic contractile capability, and the diastolic filling of the ventricles. In hypovolemia, the two dynamic variables of cardiac function, ventricular filling and myocardial contractility remain paramount and determine the stroke volume. The product of stroke volume and heart rate in turn determines the cardiac output. Increases in ventricular end-diastolic volume, reflecting venous return, cause ventricular distention. Ventricular distention in turn produces increased volume output with each stroke, the Frank Starling mechanism. Contractile function may vary independent of volume status. Changes in the contractile function shift the Starling curve up and down, producing increases or decreases in stroke volume for any given end-diastolic volume. A fundamental requirement for cardiovascular function is adequate cardiac filling, and cardiac output cannot exceed venous return. The venous system contains nearly two-thirds of the total circulating blood volume, including 20% to 30% within the splanchnic venous system. Most of this volume resides in small veins, which comprise the bulk of venous capacitance. The venous system, especially that of the splanchnic circulation, becomes important in the physiologic compensation to hypoperfusion because it serves as a dynamic reservoir for the autoinfusion of blood volume involving both active and passive mechanisms. The splanchnic circulation makes major contributions to the maintenance of venous return, therefore, it is likely that sympathetic venoconstriction is responsible for a portion of the blood mobilized from the splanchnic venous circulation. Sympathetic mediated venoconstriction in skin and skeletal muscle is probably not as significant as a source of blood volume. Selective vasoconstriction occurs in response to alpha adrenergic receptor stimulation with increased sympathetic activity in shock. Sympathetic stimulation does not cause significant vasoconstriction of either cerebral or coronary vessels, with normal blood flow maintained in these circulations. Blood flow to the skin is sacrificed early, followed by that to the kidneys and splanchnic viscera.

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23.

Shock can best be defined as:

Hypotension
Hypoperfusion of tissues.
Hypoxemia
All of the above.

Correct Answer

A. Hypoperfusion of tissues.

Explanation

Shock, no matter what the cause, is a syndrome associated with tissue hypoperfusion. Tissue hypoperfusion leads to tissue hypoxia, which may or may not be due to hypoxemia. Hypotension is a late sign of shock and, therefore, is not a good clinical indicator of the presence of tissue hypoperfusion.

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24.

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

Age over 70 years.
Chronic malnutrition.
Controlled diabetes mellitus.
Long-term steroid use.
Infection at a remote body site.

Correct Answer

A. Controlled diabetes mellitus.

Explanation

Controlled diabetes mellitus has been shown repeatedly not to be associated with increased likelihood of incisional infection provided one avoids operations on body parts that may be ischemic or neuropathic. Uncontrolled diabetes mellitus, such as ketoacidosis, is associated with a dramatic increase in surgical infection. The other parameters noted—age over 70, chronic malnutrition, regular steroid use, and an infection at a remote body site—are well-recognized adverse predictive factors and are identified in tables within the chapter.

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1

25.

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

The sodium concentration must be corrected by 5 mEq. per 100 mg. per 100 ml. elevation in blood glucose.
With normal renal function, this patient is likely to be volume overloaded.
Proper fluid therapy would be unlikely to include potassium administration
Insulin administration will increase the potassium content of cells.
Early in treatment adequate urine output is a reliable measure of adequate volume resuscitation.

Correct Answer

A. Insulin administration will increase the potassium content of cells.

Explanation

Each 100-mg. per 100 ml. elevation in blood glucose causes a fall in serum sodium concentration of approximately 2 mEq. per liter. Excess serum glucose acts as an osmotic diuretic, producing increased urine flow, which can lead to volume depletion. Insulin therapy and the correction of the patient's associated acidosis produce movement of potassium ions into the intracellular compartment.

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26.

Which of the following statement(s) is/are true concerning the autoregulation necessary to maintain oxygen consumption and oxygen delivery?

A change in oxygen consumption is followed by a proportionate change in oxygen delivery
A change in oxygen delivery is followed by a change in oxygen consumption
Increases in oxygen delivery are due solely to an increase in cardiac output
The normal ratio of oxygen delivery to consumption is 2:1

Correct Answer

A. A change in oxygen consumption is followed by a proportionate change in oxygen delivery

Explanation

The relationships between oxygen consumption and oxygen delivery represent one of the most interesting regulation systems in homeostasis. First of all, if one of the three components of oxygen delivery is abnormal, endogenous mechanisms regulate the other two until normal oxygen delivery has been restored. The various combinations of compensatory mechanisms supply adequate oxygen for systemic metabolism through a wide range of variations in oxygen delivery. When there is a change in oxygen consumption, there is a proportionate change in oxygen delivery, which occurs almost immediately, mediated completely by a change in cardiac output. Conversely, a primary change in oxygen delivery is not followed by any change in oxygen consumption. The normal ratio of oxygen delivery to consumption is approximately 5:1.

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3

27.

Which of the following statement(s) is/are correct concerning the management of an open wound?

Frequent surgical debridement is usually necessary
Water irrigation can effectively debride most wounds
Hydrogen peroxide is particularly useful in the management of open wounds
A number of the newer dressing products have clearly been shown to promote wound healing compared to simple moist occlusive dressing

Correct Answer

A. Water irrigation can effectively debride most wounds

Explanation

Although there are numerous dressing products commercially available at present, no treatment has been demonstrated to improve healing beyond that of standard treatment which adheres to basic principles. In the absence of large amounts of necrotic tissue, wound debridement does not need to be accomplished surgically. Simple water irrigation either with whirlpool or by water from a hand held shower spray can generate enough power to effectively debride most wounds. Frequent moist dressing changes can accomplish this as well, and in some cases, occlusive absorptive dressings can generate enough tissue proteases to effectively degrade proteins which the absorptive dressings remove. Deeper portions of a wound may accumulate exudate and bacteria. In such cases, water irrigation may be particularly useful. Commonly used agents such as hydrogen peroxide actually may be harmful to normal tissue and are weak oxidants and do a poor job of debriding. Enzymatic debriding agents can be effective when used properly. Most of the newer dressing products have been designed to be more absorptive and achieve moist healing without infection from excess exudate. However, it must be emphasized that as long as moist healing is achieved, there has been no evidence that one product is better than another.

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1

28.

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

The sodium concentration must be corrected by 5 mEq. per 100 mg. per 100 ml. elevation in blood glucose.
With normal renal function, this patient is likely to be volume overloaded.
Proper fluid therapy would be unlikely to include potassium administration
Insulin administration will increase the potassium content of cells.
Early in treatment adequate urine output is a reliable measure of adequate volume resuscitation.

Correct Answer

A. Insulin administration will increase the potassium content of cells.

Explanation

Each 100-mg. per 100 ml. elevation in blood glucose causes a fall in serum sodium concentration of approximately 2 mEq. per liter. Excess serum glucose acts as an osmotic diuretic, producing increased urine flow, which can lead to volume depletion. Insulin therapy and the correction of the patient's associated acidosis produce movement of potassium ions into the intracellular compartment.

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29.

In patients receiving massive blood transfusion for acute blood loss, which of the following is/are correct?

Packed red blood cells and crystalloid solution should be infused to restore oxygen-carrying capacity and intravascular volume.
Two units of FFP should be given with every 5 units of packed red blood cells in most cases
A “six pack” of platelets should be administered with every 10 units of packed red blood cells in most cases.
One to two ampules of sodium bicarbonate should be administered with every 5 units of packed red blood cells to avoid acidosis.
One ampule of calcium chloride should be administered with every 5 units of packed red blood cells to avoid hypocalcemia.

Correct Answer

A. Packed red blood cells and crystalloid solution should be infused to restore oxygen-carrying capacity and intravascular volume.

Explanation

Patients who are suffering from acute blood loss require crystalloid resuscitation as the initial maneuver to restore intravascular volume and re-establish vital signs. If 2 to 3 liters of crystalloid solution is inadequate to restore intravascular volume status, packed red blood cells should be infused as soon as possible. There is no role for “prophylactic infusion” of FFP, platelets, bicarbonate, or calcium to patients receiving massive blood transfusion. If specific indications exist patients should receive these supplemental components. In particular, patients who have abnormal coagulation tests and have ongoing bleeding should receive FFP. Patients who have depressed platelet counts along with clinical evidence of oozing (microvascular bleeding) benefit from platelet infusion. Sodium bicarbonate is not necessary, since most patients who receive blood transfusion ultimately develop alkalosis from the citrate contained in stored red blood cells. The use of calcium chloride is usually unnecessary unless the patient has depressed liver function, ongoing prolonged shock associated with hypothermia, or, rarely, when the infusion of blood proceeds at a rate exceeding 1 to 2 units every 5 minutes.

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30.

Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true?

Careful monitoring of prothrombin time and aPTT time are necessary to avoid bleeding complications
A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding
Recent (less than 10 days) major surgery is a contraindication to systemic but not regional fibrinolytic therapy
A patient with a cerebrovascular event occurring less than two months ago can be treated with fibrinolytic therapy if head CT scan is normal

Correct Answer

A. A level of serum fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding

Explanation

Fibrinolytic therapy induces a hemostatic defect through a combination of factors. Hypofibrinogenemia and fibrin degradation products inhibit fibrin polymerization and, in combination with a decrease in the clotting factors V and VIII, prolong the ability of blood to clot. However, coagulation tests in general do not correlate well with bleeding complications. A level of fibrinogen less than 100 mg/dl is associated with an increased risk of bleeding. Absolute contraindications to thrombolytic therapy include active internal bleeding, recent (less than 2 months) cerebral vascular accident, and documented left heart thrombosis. Recent (less than 10 days) major surgery, obstetric delivery, organ biopsy, or major trauma is considered a major relative contraindication to either regional or systemic thrombolytic therapy.

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1

31.

An important step in protein synthesis is transcription. Which of the following statement(s) is/are true concerning this process?

The first step in gene transcription involves separating the double helix of DNA by an enzyme known as DNA polymerase
The initial product of DNA transcription is called heterogeneous nuclear RNA which codes directly for proteins
After processing is complete, the mRNA is exported from the nucleus to the cytoplasm
Only one protein can be produced from an initial mRNA strand

Correct Answer

A. After processing is complete, the mRNA is exported from the nucleus to the cytoplasm

Explanation

Transcription of a gene begins at an initiation site associated with a specific DNA sequence, termed a promoter region. After binding to DNA, the RNA polymerase opens up a short region of the double helix to expose the nucleotides. Once the two strands of DNA are separated, the strand containing the promoter acts as a template to which ribonucleoside triphosphates base pair by hydrogen bonds. The initial products of transcription are known as heterogeneous nuclear RNA because of their large size variation. These primary transcripts are then processed to form mRNA. RNA splicing accounts for mature RNA being much shorter than nuclear RNA. Moreover, alternative splicing can lead to the production of different mRNA molecules and in some cases different proteins from the same gene. mRNA is exported from the nucleus only after processing is complete.

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32.

Which of the following statements about extracellular fluid are true?

The total extracellular fluid volume represents 40% of the body weight.
The plasma volume constitutes one fourth of the total extracellular fluid volume
Potassium is the principal cation in extracellular fluid.
The protein content of the plasma produces a lower concentration of cations than in the interstitial fluid
The interstitial fluid equilibrates slowly with the other body compartments.

Correct Answer

A. The plasma volume constitutes one fourth of the total extracellular fluid volume

Explanation

The total extracellular fluid volume represents 20% of body weight. The plasma volume is approximately 5% of body weight. Sodium is the principal cation. The Gibbs-Donan equilibrium equation explains the higher total concentration of cations in plasma. Except for joint fluid and cerebrospinal fluid, the majority of the interstitial fluid exists as a rapidly equilibrating component.

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33.

In “catabolic” surgical patients, which of the following changes in body composition do not occur?

Lean body mass increases.
Total body water increases.
Adipose tissue decreases.
Body weight decreases.

Correct Answer

A. Lean body mass increases.

Explanation

Lean body mass represents the body compartment that contains protein. Because critical illness stimulates proteolysis and increased excretion of body nitrogen, this compartment is consistently reduced, not increased. The change in body composition is associated with a loss of body weight, an increase in total body water, and a decrease in body fat.

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1

34.

The characteristic changes that follow a major operation or moderate to severe injury do not include the following:

Hypermetabolism.
Fever
Tachypnea
Hyperphagia
Negative nitrogen balance.

Correct Answer

A. Hyperphagia

Explanation

The characteristic metabolic response to injury includes hypermetabolism, fever, accelerated gluconeogenesis, and increased proteolysis (creating a negative nitrogen balance). Food intake is generally impossible because of abdominal injury or ileus. With time, food intake increases, but the patient generally experiences anorexia, not hyperphagia.

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2

35.

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

The sodium concentration must be corrected by 5 mEq. per 100 mg. per 100 ml. elevation in blood glucose.
With normal renal function, this patient is likely to be volume overloaded.
Proper fluid therapy would be unlikely to include potassium administration
Insulin administration will increase the potassium content of cells.
Early in treatment adequate urine output is a reliable measure of adequate volume resuscitation.

Correct Answer

A. Insulin administration will increase the potassium content of cells.

Explanation

Each 100-mg. per 100 ml. elevation in blood glucose causes a fall in serum sodium concentration of approximately 2 mEq. per liter. Excess serum glucose acts as an osmotic diuretic, producing increased urine flow, which can lead to volume depletion. Insulin therapy and the correction of the patient's associated acidosis produce movement of potassium ions into the intracellular compartment.

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1

36.

Advantages of epidural analgesia include:

Earlier mobilization after surgery.
Earlier return of bowel function.
Shorter hospitalizations.
Decreased stress response to surgery.
All of the above

Correct Answer

A. All of the above

Explanation

Epidural analgesia include excellent pain relief, decreased sedation with more rapid recovery to presurgical levels of consciousness, earlier mobilization after surgery with increased ability to co-operate with respiratory therapy and physical therapy. Following vascular surgery epidural analgesia may also improve graft flow through mild sympathetic blockade. Earlier return of bowel function, decreased stress response, shorter hospitalizations, and decreased morbidity have all been associated with epidural analgesia.

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37.

Phases of multiorgan failure will include:

Generalized increased capillary permeability
A hypermetabolic state
Organ malfunction
All of the above

Correct Answer

A. All of the above

Explanation

Clinically the multiple-organ failure patient progresses through well-defined phases. These phases include: Phase 1—a generalized increased capillary permeability resulting in edema, weight gain, and intravenous volume replacement, increased protein concentration in urine and lymph. Although the pulmonary microvasculature has been most thoroughly studied, it is apparent that the lung is simply the most obvious end organ in a generalized permeability defect. Phase 2—A hypermetabolic state, with increased oxygen consumption and a compensatory increase in oxygen delivery characterized by tachycardia and high cardiac output. This condition following systemic ischemic and reperfusion is similar to hypermetabolism following endotoxemia, localized sterile inflammation, and infusion of stress hormones, suggesting a common mechanism. Phase 3—Organ malfunction due to localized edema and cellular injury, particularly in the kidney, liver, brain, and host defense system. Hemorrhagic shock predisposes to bacterial translocation and endotoxin absorption from the intestine. Phase 4—In the absence of systemic sepsis, organs may recover to normalcy or may be irreversibly damaged, leading to a need for chronic support. If the organ failure phases lead to systemic infection or irreversible tissue damage in the lung or brain, the death of the entire organ is likely.

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38.

Which of the following statement(s) is/are true concerning the role of glutamine in total parenteral nutrition?

Glutamine is an essential amino acid
Glutamine appears to be of primary benefit in critical illness
Glutamine is included in most standard TPN solutions
Glutamine is the primary energy source for intestinal mucosal cells of the small bowel and colon

Correct Answer

A. Glutamine appears to be of primary benefit in critical illness

Explanation

Glutamine is the most studied gut-specific nutrient. Glutamine has been classified as a nonessential or nutritionally dispensable amino acid since glutamine can be synthesized in adequate quantities from other amino acids and precursors. Glutamine is not included in most nutritional formulas and has been eliminated from TPN solutions because of its relative instability and short half life compared to other amino acids. With few exceptions, glutamine is present in oral enteral diets but only at relatively low levels characteristic of the concentration in most animal and plant stores (about 7% of total amino acids). Several recent studies, however, have demonstrated that glutamine may be an essential amino acid during critical illness, particularly as it relates to supporting the metabolic requirements of the intestinal mucosa. These studies demonstrate that dietary glutamine is not required during states of health but appears to be beneficial when glutamine depletion is severe and/or when intestinal mucosa is damaged by insults such as chemotherapy or radiation therapy. The addition of glutamine to enteral diet reduces the incidence of gut translocation but these improvements are dependent upon the amount of supplemental glutamine and the type of insult studied. Glutamine-enriched TPN partially attenuates villous atrophy that develops during parenteral nutrition. The use of intravenous glutamine in patients appears to be safe and effective in its ability to maintain muscle glutamine stores and improve nitrogen balance. In contrast to glutamine, short chain fatty acids are primary energy source for colonocytes.

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39.

All of the following are true about neurogenic shock except:

There is a decrease in systemic vascular resistance and an increase in venous capacitance.
Tachycardia or bradycardia may be observed, along with hypotension.
The use of an alpha agonist such as phenylephrine is the mainstay of treatment
Severe head injury, spinal cord injury, and high spinal anesthesia may all cause neurogenic shock.

Correct Answer

A. The use of an alpha agonist such as phenylephrine is the mainstay of treatment

Explanation

Neurogenic shock occurs when severe head injury, spinal cord injury, or pharmacologic sympathetic blockade leads to sympathetic denervation and loss of vasomotor tone. Both arteriolar and venous vessels dilate, causing reduced systemic vascular resistance and a great increase in venous capacitance. The patient's extremities appear warm and dry, in contrast to those of a patient in cardiogenic or hypovolemic shock. Tachycardia is frequently observed, though the classic description of neurogenic shock includes bradycardia and hypotension. Volume administration to fill the expanded intravascular compartment is the mainstay of treatment. The use of alpha-adrenergic agonist is infrequently necessary to treat neurogenic shock.

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40.

Which of the following statement(s) is/are true concerning nutritional support of the injured patient?

The goal of nutritional support is maintenance of body cell mass and limitation of weight loss to less than 25% of preinjury weight
Under-nutrition may compromise the patient’s available defense mechanisms
Nutritional support is an immediate priority for the trauma patient
Fifty percent of non-nitrogen caloric requirements should be provided in the form of fat

Correct Answer

A. Under-nutrition may compromise the patient’s available defense mechanisms

Explanation

Metabolic response to injury results in increased energy expenditure. If energy intake is less than expenditure, oxidation of body fat stores and erosion of lean body mass will occur with resultant loss of weight. When weight loss exceeds 10–15% of body weight, the complications of malnutrition interact with disease processes, with increased morbidity and mortality rates. The goal of nutritional support is maintenance of body cell mass and limitation of weight loss to less than 10% preinjury. The major impact of nutritional support in the trauma patient is to aid host defense. Under-nutrition may compromise the available host defense mechanism and may thus increase the likelihood of invasive sepsis, multiple organ system failure, and death. Resuscitation, oxygenation and arrest of hemorrhage are immediate priorities for survival. Nutritional support is an essential part of the metabolic care of the critically ill patient and should be instituted after resuscitation before significant weight loss occurs. The nutritional requirements of a trauma patient can be determined by determining basal metabolic rate with appropriate increases based on extent of injury and hospital activity. After initial determination of nitrogen requirements, caloric requirements should be distributed at a ratio of 70% as glucose and 30% as fat.

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41.

Phases of multiorgan failure will include: Which of the following statement(s) is/are true concerning the assessment of protein reserve?

Conventional serum proteins such as albumin and globulin are early indicators of malnutrition
The total lymphocyte count reflects immune status and not nutrition
Antigen skin testing reflects patient immunity and not nutrition
Measurement of urea excretion in urine can be used as a measurement of protein breakdown

Correct Answer

A. Measurement of urea excretion in urine can be used as a measurement of protein breakdown

Explanation

Since protein is the functional and structural chemical of the body, most nutritional assessment techniques are estimates of protein reserves. The actual nitrogen balance can be measured by measuring the amount of nitrogen excreted. This is most conveniently done by measuring the amount of urea excreted in the urine, assuming that urea constitutes 85% of the total nitrogen excretion. Knowing nitrogen excretion, the amount of protein catabolized can be estimated and compared with the amount of protein ingested by the patient. Indirect assessments of protein reserves are based on single measurements of body substances that are dependent on rapid protein synthesis for maintenance of normal levels. Conventional serum proteins such as albumin and globulin are not affected by malnutrition until it is very severe. Proteins such as prealbumen and transferrin, which turn over more rapidly, are better indicators of protein status. Lymphocytes are rapidly destroyed and protein is required for the formation of new cells. Consequently, the absolute lymphocyte count is a useful measure of the status of protein reserves. The lymphocyte count is considered by some the best single “static” measurement characterizing nutritional status. Protein is also required for synthesizing the cells and mediators involved in skin test reactivity. Although skin test reactivity is a manifestation of lymphocyte-mediated immunity, its usefulness in patient assessment is probably that of assessment of the inflammatory response than lymphocyte activity per se. Some chronically and acutely malnourished patients convert from reactive to anergic, and reactivity can be restored by nutritional repletion.

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4

42.

Which of the following statement(s) is/are true concerning the vascular response to injury?

Vasoconstriction is an early event in the response to injury
Vasodilatation is a detrimental response to injury with normal body processes working to avoid this process
Vascular permeability is maintained to prevent further cellular injury
Histamine, prostaglandin E2 (PGE2) and prostacyclin (PGI2) are important mediators of local vasoconstriction

Correct Answer

A. Vasoconstriction is an early event in the response to injury

Explanation

After wounding, there is transient vasoconstriction mediated by catecholamines, thromboxane, and prostaglandin F2 (PGF2a). This period of vasoconstriction lasts for only five to ten minutes. Once a clot has been formed and active bleeding has stopped, vasodilatation occurs in an around the wound. Vasodilatation increases local blood flow to the wounded area, supplying the cells and substrate necessary for further wound repair. The vascular endothelial cells also deform, increasing vascular permeability. The vasodilatation and increased endothelial permeability is mediated by histamine, PGE2, and prostacyclin as well as growth factor VEGF (vascular endothelial cell growth factor). These vasodilatory substances are released by injured endothelial cells and mast cells and enhance the egress of cells and substrate into the wound and tissue.

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43.

Which of the following statement(s) is/are true concerning septic shock?

The clinical picture of gram negative septic shock is specifically different than shock associated with other infectious agents
The circulatory derangements of septic shock precede the development of metabolic abnormalities
Splanchnic vascular resistance falls in similar fashion to overall systemic vascular resistance
Despite normal mechanisms of intrinsic expansion of the circulating blood volume, exogenous volume resuscitation is necessary

Correct Answer

A. Despite normal mechanisms of intrinsic expansion of the circulating blood volume, exogenous volume resuscitation is necessary

Explanation

The clinical findings in sepsis and septic shock represent the host response to infection. Gram-positive and gram-negative bacteria, viruses, fungi, rickettsiae, and protozoa have all been reported to produce a clinical picture of septic shock, but the overall response is independent of the specific type of invading organism. Septic shock develops as a consequence of the combination metabolic and circulatory derangements accompanying the systemic infection. It appears that the circulatory deficits are preceded by the metabolic abnormalities induced by infection. In fact, the circulatory changes in hyperdynamic sepsis appear to be an adaptive response to the underlying metabolic dysfunction. Cardiac output is high and systemic vascular resistance low in hyperdynamic septic shock. However, splanchnic vasoconstriction is pronounced even in the absence of systemic hypotension and even though systemic vascular resistance is reduced. Expansion of circulating blood volume can occur through either transcapillary refill or fluid resuscitation. Due to the ongoing inflammatory mediator-induced increases in capillary permeability and continued loss of intravascular volume, exogenous volume resuscitation must be provided to restore venous return and ventricular filling.

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44.

Which of the following statements regarding cytokines is incorrect?

Cytokines act directly on target cells and may potentiate the actions of one another.
Interleukin 1 (IL-1) is a major proinflammatory mediator with multiple effects, including regulation of skeletal muscle proteolysis in patients with sepsis or significant injury.
Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability.
Tumor necrosis factor alpha (TNF-a), despite its short plasma half-life, appears to be a principal mediator in the evolution of sepsis and the multiple organ dysfunction syndrome because of its multiple actions and the secondary cascades that it stimulates

Correct Answer

A. Platelet-activating factor (PAF) is a major cytokine that results in platelet aggregation, bronchoconstriction, and increased vascular permeability.

Explanation

Cytokines are soluble peptide molecules that are synthesized and secreted by a number of cell types in response to injury, inflammation, and infection. Cytokines, which include the interleukins, tumor necrosis factor, colony-stimulating factors, and the interferons, comprise only one category of inflammatory mediators involved in the host response. Endotoxin, complement fragments, eicosanoids, kinins, nitric oxide, oxidants, and PAF are noncytokine mediators that also have important roles in the systemic inflammatory response. IL-1 and TNF-a, like other cytokines, have multiple effects on target cells and potentiate the actions of other mediators to produce an amplified inflammatory response. TNF-a is thought to play a central role in the stress response, particularly in response to endotoxemia.

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45.

Scar formation is part of the normal healing process following injury. Which of the following tissues has the ability to heal without scar formation?

Liver
Skin
Bone
Muscle

Correct Answer

A. Bone

Explanation

Every tissue in the body undergoes reparative processes after injury. Bone has the unique ability to heal without scar and liver has the potential to regenerate parenchyma, the only organ that has maintained that ability in the adult human. Although liver does regenerate, it often heals with scar (cirrhosis) as well. With these exceptions, all other mature human tissues heal with scar.

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1

46.

Which of the following statement(s) is/are true concerning the indications and administration of nutritional support to cancer patients?

Preoperative nutritional support should be provided to all patients with cancer
To be effective, preoperative nutrition must be given for at least two weeks preoperatively
Parenteral nutrition is the preferred route of feeding for all cancer patients
Standard total parenteral nutrition solutions maintain integrity of the small bowel
None of the above

Correct Answer

A. None of the above

Explanation

The role of nutritional support in the cancer patient remains an important component of overall therapy. Preoperative nutritional support should be given only to those patients who do not require an emergency operation and who have severe weight loss (> 15% of pre-illness body weight) and a serum albumen < 2.9 mg%. Preoperative nutrition (enteral or parenteral) should not be given for longer than 7 to 10 days. Enteral nutrition is always the preferred route of feeding cancer patients if the GI tract is functional. There are several benefits of using the bowel lumen for nutrient delivery. The trophic effects of enteral feeding on small bowel mucosa have been well described. The integrity of the mucosal lining is maintained and it may provide an effective barrier to intraluminal enteric organisms which might otherwise translocate into the systemic circulation. Atrophic changes may be seen in the intestinal epithelium after several days of bowel rest; this atrophy is not reversed by currently available total parenteral nutrition solutions.

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47.

Which of the following statements about extracellular fluid are true?

The total extracellular fluid volume represents 40% of the body weight.
The plasma volume constitutes one fourth of the total extracellular fluid volume
Potassium is the principal cation in extracellular fluid.
The protein content of the plasma produces a lower concentration of cations than in the interstitial fluid
The interstitial fluid equilibrates slowly with the other body compartments.

Correct Answer

A. The plasma volume constitutes one fourth of the total extracellular fluid volume

Explanation

The total extracellular fluid volume represents 20% of body weight. The plasma volume is approximately 5% of body weight. Sodium is the principal cation. The Gibbs-Donan equilibrium equation explains the higher total concentration of cations in plasma. Except for joint fluid and cerebrospinal fluid, the majority of the interstitial fluid exists as a rapidly equilibrating component.

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48.

Which of the following statements regarding whole blood transfusion is/are correct?

Whole blood is the most commonly used red cell preparation for transfusion in the United States.
Whole blood is effective in the replacement of acute blood loss.
Most blood banks in the United States have large supplies of whole blood available.
The use of whole blood produces higher rates of disease transmission than the use of individual component therapies

Correct Answer

A. Whole blood is effective in the replacement of acute blood loss.

Explanation

Whole blood is effective as a replacement fluid for acute blood loss because it provides both volume and oxygen-carrying capacity (red blood cells). It is rarely used in the United States nowadays, and most blood banks do not provide whole blood transfusions. It is significantly more efficient to separate donated blood into its components. In this manner, the red blood cell mass can be used to provide oxygen-carrying capacity, the plasma can be used for factor replacement, and the platelets and white cells can be used for patients deficient in these components. The use of whole blood to replace acute blood loss is associated with lower disease transmission rates than the use of packed red blood cells, fresh frozen plasma, and platelets, each from a different donor.

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49.

Which of the following statement(s) concerning intravenous nutritional support is/are true?

Concentrations of glucose no higher than 5% should be used to avoid peripheral vein sclerosis
A major disadvantage of the peripheral technique is limited caloric delivery
If total parenteral nutrition is required, access to the superior vena cava via the external jugular vein is the most suitable site
Venous thrombosis is an uncommon complication for long-term central vein catheterization

Correct Answer

A. A major disadvantage of the peripheral technique is limited caloric delivery

Explanation

Although peripheral access can be used for intravenous nutrition, the major disadvantage of this technique is limited caloric delivery to meet catabolic demands within tolerated fluid limits. Infusion of glucose (up to 10%), amino acid solutions, and fat emulsions can be administered peripherally but these solutions must be nearly isotonic to avoid peripheral vein sclerosis. The preferred method of access for total parenteral nutrition is into the superior vena cava by cutaneous cannulation of the subclavian vein. Alternative sites include the internal and external jugular vein but the catheter exiting from the neck region makes it more difficult to secure and maintain a sterile dressing. Complications from long-term central venous catheterization include venous thrombosis and venous catheter-related infection. Thrombosis of central vessels is a complication which is often overlooked. The clinical suspicion of subclavian vein thrombosis is only about 3%, whereas studies that use phlebography or radionucleotide venography indicate the incidence is as high as 35%.

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Basic Surgery (100q).1

Which of the following statement(s) is/are true concerning the cell function of phagocytosis?

Quiz Preview

Which of the following statement(s) is/are true concerning the cell function of phagocytosis?

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

Advantages of epidural analgesia include:

Which of the following factors have been demonstrated to promote wound healing in normal individuals?

The characteristic changes that follow a major operation or moderate to severe injury do not include the following:

In patients receiving massive blood transfusion for acute blood loss, which of the following is/are correct?

In “catabolic” surgical patients, which of the following changes in body composition do not occur?

Which of the following statement(s) is/are true concerning pulmonary edema?

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

Which of the following statement(s) is/are true concerning the compensatory mechanisms and treatment of metabolic acidosis?

Which of the following statement(s) is/are correct concerning the body fluid compartments?

Intensive insulin therapy:

Which of the following statement(s) is/are true concerning the treatment of pulmonary interstitial edema?

Shock can best be defined as:

A striking feature of living cells is a marked difference between the composition of the cytosol and the extracellular milieu. Which of the following statement(s) concerning the mechanisms of maintenance of these differences is/are true?

Glucose overload results in increased CO 2 production. Which of the following statements are true?

All of the following are true about neurogenic shock except:

Narcotics are commonly used in the administration of general anesthesia. Which of the following statement(s) is/are true concerning this class of agents.

Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true?

Which of the following statements about the presence of gallstones in diabetes patients is/are correct?

Which of the following statement(s) is/are correct concerning the cardiovascular response to shock?

Shock can best be defined as:

Which of the following is/are not associated with increased likelihood of infection after major elective surgery?

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

Which of the following statement(s) is/are true concerning the autoregulation necessary to maintain oxygen consumption and oxygen delivery?

Which of the following statement(s) is/are correct concerning the management of an open wound?

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

In patients receiving massive blood transfusion for acute blood loss, which of the following is/are correct?

Bleeding complications are frequently associated with fibrinolytic therapy. Which of the following statement(s) concerning complications of fibrinolytic therapy is/are true?

An important step in protein synthesis is transcription. Which of the following statement(s) is/are true concerning this process?

Which of the following statements about extracellular fluid are true?

In “catabolic” surgical patients, which of the following changes in body composition do not occur?

The characteristic changes that follow a major operation or moderate to severe injury do not include the following:

1. Which of the following statements are true of a patient with hyperglycemia and hyponatremia?

Advantages of epidural analgesia include:

Phases of multiorgan failure will include:

Which of the following statement(s) is/are true concerning the role of glutamine in total parenteral nutrition?

All of the following are true about neurogenic shock except:

Which of the following statement(s) is/are true concerning nutritional support of the injured patient?

Phases of multiorgan failure will include: Which of the following statement(s) is/are true concerning the assessment of protein reserve?

Which of the following statement(s) is/are true concerning the vascular response to injury?

Which of the following statement(s) is/are true concerning septic shock?

Which of the following statements regarding cytokines is incorrect?

Scar formation is part of the normal healing process following injury. Which of the following tissues has the ability to heal without scar formation?

Which of the following statement(s) is/are true concerning the indications and administration of nutritional support to cancer patients?

Which of the following statements about extracellular fluid are true?

Which of the following statements regarding whole blood transfusion is/are correct?

Which of the following statement(s) concerning intravenous nutritional support is/are true?